Allow gsid to create alternative installation directory

Bug: 275484855
Test: adb shell gsi_tool install -n -w \
  --gsi-size $(du -b system.raw|cut -f1) \
  --install-dir /data/gsi/oem --userdata-size 8589934592 < system.raw
Change-Id: I46aa48fafec2f3845fa1a5139afb8c03db6b0d4e
diff --git a/private/gsid.te b/private/gsid.te
index e795cea..9391016 100644
--- a/private/gsid.te
+++ b/private/gsid.te
@@ -150,7 +150,7 @@
 allow gsid {
       gsi_data_file
       ota_image_data_file
-}:dir rw_dir_perms;
+}:dir create_dir_perms;
 allow gsid {
       gsi_data_file
       ota_image_data_file